No idea, but if it helps, attached is the MCP v1.39 configuration I've been using without problems for years with this A4000T/060. Now with OS3.1.4, previously 3.9.
You'll need to rename it to MCP.config and copy it to ENVARC:MCP2/MCP.config
Obviously backup your existing config first.
I'm also running MCP from WBstartup. Failing that, you could try disabing some of the non-standard stuff in startup-sequence to see if that makes a difference.
